The present invention resides in an extrusion press stem which is characterized by at least one channel running approximately axially through it from a shape giving die. The stem is used in the indirect extrusion of materials, in particular billets of light metal.
When an extrusion billet, heated to the extrusion temperature, is hot formed into sections or rods, the billet which is surrounded by a container, is usually pushed through a stationary die by the stem of a hydraulic press.
In extrusion by the so called indirect extrusion process, the shaping die is pushed inside the stationary container after which a new billet is introduced and extruded.
The die is positioned at one end of the stem, which is highly stressed both thermally and mechanically and which has to be hollow since the extruded material passes out of the press through the stem. In supporting the die during extrusion the whole of the extrusion force, which usually involves torsional and bending stresses as well as purely compressive forces, acts on the moving stem.
A known extrusion stem of the kind described at the beginning is made up of a number of individual disc shaped parts which serve as members for supporting the shaping die. These discs are held together by a circumferential guiding sleeve which has to take up all the bending and torsional forces which develop. If the discs in the sleeve twist out of place, this leads to considerable interruption in production.
It is the principal object of the present invention to develop an extrusion stem with at least one channel running approximately axially through it, and which is able to withstand the compressive, bending and torsional stresses which develop during extrusion and which is also easily constructed and easily adapted to suit various conditions.